JP2002239669A - Form rolling die, form-rolled article manufacturing method, small motor using the form-rolled article, and manufacturing method of the motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method in which the manufacturing cost can be reduced, and the productivity can be heightened by jointly forming and roughening an engagement structure by using a form rolling method when manufacturing parts having the engagement structure such as a screw and a gear. SOLUTION: Smooth pre-machined areas 112a and 122a of the predetermined length (the length of not less than one form rolling pitch) from a front end of parallel parts are formed on the parallel parts 112 and 122 formed behind biting parts 111 and 121, and post-machined areas 112b and 122b including roughened areas 112br and 122br are formed therebehind.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rolled die, a rolled product, a method of manufacturing a rolled product, a small motor using the rolled product, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In general, a technique for roughening the surface of a meshing structure of a component having a meshing structure such as a screw or a gear is known. For example, there is known a thread rolled product in which the surface of the screw is roughened to make it difficult to loosen. Further, as described in Japanese Patent No. 2636958, a worm gear is known in which the tooth surface is roughened to ensure reversal resistance.

[0003]

However, when manufacturing a screw or gear having the above-described roughened portion, after forming the screw or gear, the part is subjected to a roughening treatment such as shot blasting. Therefore, there is a problem that it takes time and increases the manufacturing cost. In particular, in the field where high wear resistance and shape accuracy are required, it may be necessary to perform a surface hardening treatment to increase the durability of the rough surface after roughening the surface of the screw or gear, In this case, the manufacturing cost further increases.

Accordingly, the present invention has been made to solve the above-mentioned problems, and an object of the present invention is to form a meshing structure using a rolling method when manufacturing a component having a meshing structure such as a screw or a gear. By performing both processing and surface roughening,
An object of the present invention is to provide a novel manufacturing method capable of reducing the manufacturing cost and increasing the productivity.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a rolling die of the present invention is provided with a biting portion on the front side into which an original material is introduced, for forming a rolled product having a meshing structure. And a rolled die having a die surface provided with a main processing portion that determines the shape of the meshing structure on the rear side of the biting portion, wherein the die surface is rearward by a predetermined distance from a front end of the main processing portion. A roughened surface forming portion for roughening the surface of the engagement structure from the start position away from the rear surface to the rear is formed.

According to the present invention, by providing the rolling die with the rough surface forming portion, the meshing structure can be formed and the surface thereof can be roughened, so that the manufacturing cost can be reduced and the productivity can be reduced. Can be enhanced.

When a rolled product having an interlocking structure is formed by using a rolling die, the original material is transferred to a main working portion while undergoing plastic working along a biting portion of the die surface. An almost perfect interlocking structure is formed. The main processing portion generally corresponds to a portion called a parallel portion of the die. At this time, usually, a large processing stress is applied to the vicinity of the front end of the main processing portion, so that the die surface of the portion is easily worn. In the rolling die of the present invention, avoiding the vicinity of the front end of the main processing portion to which a large processing stress is applied, a position away from the front end of the main processing portion by a predetermined distance rearward is set as a start position, and a rough surface is formed rearward from there. Since the formation portion is formed, it is possible to prevent wear of the rough surface formation portion. Therefore, the durability of the rolling die is improved, and the molding state can be maintained for a long time, so that the manufacturing cost can be further reduced.

[0008] In the present invention, it is preferable that the start position is separated from the front end of the main processing portion by one or more rolling pitches. Since the processing stress applied to the die surface gradually decreases from the front end of the main processing portion toward the rear, the above-described effect is exerted as long as the start position of the roughened surface forming portion is located behind the front end of the main processing portion. In particular, since the starting position is at least one rolling pitch backward with respect to the front end of the main processing section, the rough surface forming section is formed after the original material is formed by the main processing section over the entire circumference. Therefore, abrasion of the rough surface forming portion can be further reduced.

In the present invention, it is preferable that the starting position is located at a distance corresponding to a plurality of rolling pitches or more rearward from a front end of the main processing portion. In this case, there is an interval of a plurality of rolling pitches or more between the front end of the main processing portion and the start position of the rough surface forming portion. When it becomes impossible to perform the roughening, even if the rough surface forming portion is extended by one rolling pitch to the front end side of the main processing portion by modifying the die surface, the starting position of the rough surface forming portion still remains. 1 from the front end of the main processing section
Since it is separated by the rolling pitch or more, the rolled product can be further processed by a new extension of the rough surface forming portion. Therefore, the life of the rolling die can be substantially extended.

In the present invention, it is preferable that the rough surface forming portion is formed by causing abrasive grains to collide with the die surface. The rough surface forming portion can be easily and reliably formed by colliding abrasive grains with a die surface roughly formed in advance (for example, a shot blast method).

In the present invention, the rough surface forming portion is formed in a region limited in a width direction in a region behind the start position of the die surface so as to roughen only a part of the engagement structure. It is preferred that Since the rough surface forming portion is formed in a region limited in the width direction in a region behind the starting position of the die surface of the rolled die, only a necessary portion of the meshing structure of the rolled product has a rough surface. When the rough surface forming portion is worn out, by performing a modification process of newly providing a rough surface forming portion in a region that is not the rough surface forming portion in the area behind the starting position when the rough surface forming portion is worn out. In addition, the service life of the rolling dies can be substantially extended. Here, the width direction is a direction perpendicular to the processing direction from the front side to the rear side of the die surface (in the case of a flat die, a linear direction perpendicular to the processing direction, and in the case of a through (walking) round die, The direction of rotation (direction of die rotation) orthogonal to the processing direction (axial direction).

In the present invention, it is preferable that a plurality of the rough surface forming portions are formed only in positions separated from each other in a width direction of the die surface. Since the plurality of rough surface forming portions are formed only at positions separated from each other, the meshing structure can be roughened by using only a part of the plurality of rough surface forming portions. ,
By changing the rough surface forming portion to be used and performing the processing, the life of the dice can be substantially extended.

Next, a method for manufacturing a rolled product according to the present invention is a method for manufacturing a rolled product having a step of forming an interlocking structure with the original material, wherein the rolling process is performed on the original material. An initial rolling step of forming the meshing structure, and a rough surface forming step of roughening the surface of the meshing structure while maintaining the meshing structure after the initial rolling step are provided.

In the present invention, it is preferable that in the initial rolling step, a plurality of rolling cycles are repeatedly performed on the original material. Here, the rolling forming cycle refers to a cycle in which forming processing is performed on the entire circumference of the original material, and in the case of performing processing using a rolling die, a cycle corresponding to processing performed by a die surface of one rolling pitch.

In the present invention, it is preferable that the initial rolling step and the rough surface forming step are continuously performed on an integrated die surface.

In the present invention, after the rolling process of the rolled product is performed on the die surface, a rough surface forming surface portion for performing the rough surface forming step is formed on the die surface by the initial rolling. It is preferable to perform a correction process for extending the inside of the initial rolling surface portion for performing the step, and then further perform a rolling process for another rolled product.

In the present invention, it is preferable that in the rough surface forming step, only a part of the surface of the meshing structure is subjected to a roughening treatment.

In the present invention, after the rolling process of the rolled product is performed on the die surface, a limited formation area of a rough surface forming surface portion for performing the rough surface forming step on the die surface. It is preferable to perform a correction process for enlarging the diameter of the rolled product, and then perform a rolling process for another rolled product.

Next, a small motor with a speed reducer according to the present invention is a small motor with a speed reducer in which the output of the small motor is transmitted by a helical gear or a worm wheel and a worm. It is characterized by having been done.

In the present invention, the helical gear or the worm wheel can be reduced by two steps.

Further, the method of manufacturing a small motor with a speed reducer according to the present invention is a method of manufacturing a small motor with a speed reducer in which the output of the small motor is transmitted by a helical gear or a worm wheel and a worm. It is formed by rolling with a rolling die. Here, the above-mentioned rolling die is used for the rolling process on the worm surface, and the above-described method for manufacturing a rolled product can be applied.

[0022]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a rolling die and a method of manufacturing a rolled product according to the present invention.

[First Embodiment] FIG. 1 shows the structure of a rolling die (flat die) 10 according to a first embodiment. Figure 1
(A) is a flat die 11 constituting one of the rolling dies 10.
1 shows a cross-sectional view and a plan view as viewed in a processing direction S of FIG.
2B shows a cross-sectional view and a plan view of the other flat die 12 of the rolling die 10 as viewed in the processing direction S.

The flat dies 11 and 12 each have a die surface 1
1a and 12a, and these die surfaces 11a and 12a
And the dice surfaces 11a, 1
The original material 20A is rolled by reciprocating substantially parallel to 2a. Here, the original material 20A is a thread rolled product 2 described later.
The portion corresponding to the zero screw portion 23 is formed in a cylindrical shape.

On the die surfaces 11a and 12a, forming grooves extending in a direction slightly inclined with respect to the processing direction S for forming screw threads are entirely formed. On the die surfaces 11a and 12a, biting portions 111 and 121 inclined toward the processing direction S and parallel portions 112 and 122 substantially parallel to the processing direction S are sequentially formed. Further, a relief portion 123 is provided on the die surface 12a, which is inclined in the processing direction S of the parallel portion 122. Parallel part 11
Reference numeral 2122 denotes a forming operation surface for determining a final screw shape.

In the parallel portion 112 of the die surface 11a, a front processing region 112a is provided on the front side in the processing direction S, and a rear processing region 212b is provided behind the front processing region 112a. In the post-processing region 212b, two rough surface processing region portions 112br, 112br formed in a limited manner in the width direction W, that is, on both sides in the width direction W are provided.

In the parallel portion 122 of the die surface 12a, a front processing region 122a is provided on the front side in the processing direction S, and a rear processing region 122b is provided behind the front processing region 122a. After this, the width direction W
Two roughened surface processing regions 122 br and 122 br are formed on both sides in a limited manner.

In the relief portion 123 of the die surface 12a, two rough surface processing region portions 123r, 123r, formed successively from the rough surface processing region portion 122br of the parallel portion 122.
123r is provided.

The front processing regions 112a and 122a extend from the front ends of the parallel portions 112 and 122 to the front ends of the rear processing regions 112b, and the length thereof is determined by the rolling pitch (one pitch of the thread to be rolled is equal to the die pitch). The length is preferably measured in the processing direction S of the surface, i.e., the length of the die surface in the processing direction S required for forming one round of the thread once. Pre-processing areas 112a, 122a
The reason for setting the length to be equal to or longer than one rolling pitch is that the entire circumference of the thread is formed once at one rolling pitch in the pre-processing area,
This is because the processing stress applied to the rough surface processing region portions 112br and 122br is reduced, and the durability of the rough surfaces of the rough surface processing regions 112br and 122br can be increased.

The length of the pre-processed regions 112a and 122a as viewed in the processing direction S is previously set to be equal to or greater than two rolling pitches, and preferably equal to or greater than three rolling pitches. When 122br wears out,
The rough surface processing region portions 112br and 122br are changed to the pre-processing region 1
By performing the modification processing so as to extend into (ie, forward) into 12a and 122a, it is possible to maintain the rough surface machining ability. Therefore, the service life of the rolling die can be substantially extended by performing such a modification. In this case, it is preferable that, even after the correction processing, the length of the non-roughened pre-processing region in the processing direction S remains at least one rolling pitch.
The reason is the same as described above.

The thread once formed in the front processing regions 111 and 121 has a rough surface processing region 11
Roughening is performed on 2br, 122br, and 123r. The surface roughness of the roughened region is formed to a surface roughness substantially corresponding to the surface roughness of the rough screw portion 23b of the thread rolling product 20 described later. Specifically, Ry = 1.0-100
It is formed within the range of μm. In particular, Ry = 10 to 30 is provided on the threaded portion for preventing loosening or on the tooth surface of the gear for controlling frictional resistance.
μm is preferred. Here, the width Wr of the rough surface processing region is formed corresponding to the rough surface forming range of the rolled product, and in the present embodiment, the rough surface thread portion 23 of the thread rolled product 20 described later.
It is formed equal to the length of b.

In the present embodiment, when the roughened region is worn, the die is modified so as to extend the roughened region in the width direction W, thereby substantially extending the life of the die. Is also possible. In this case, in accordance with the width direction position of the newly formed rough surface processing area portion,
By adjusting the position of the original material (relative position in the width direction with respect to the die), substantially the same rough surface thread portion can be formed in the thread rolled product.

In this embodiment, two rough surface processing regions 112 br and 122 br of the post-processing region are formed in the width direction so as to be spaced apart from each other, and only one of them has the original shape indicated by a dashed line in FIG. It is configured such that a rough surface screw portion 23b described later can be formed on the material 20A. As a result, the orientation of the original material 20A with respect to the flat dies 11 and 12 is reversed in the width direction, or
By exchanging 1, 12 for use in the opposite direction (for example, the movable side and the fixed side are reversed), it is possible to similarly form the thread portion roughened in the other rough surface forming region. it can. Therefore, the life of the rolling dies can be substantially doubled.

In the above-described embodiment, the rough surface forming region is formed on both flat dies 11 and 12, but the rough surface forming region is provided only on the die surface of one of the flat dies. It can also be molded.

[Specific Example 1 of Rolled Product] Next, the structure of a thread rolled product manufactured using the rolling die of the first embodiment will be described. The thread rolled product 20 shown in FIG. 2A is a tapping screw made of steel or the like, and includes a head 21, a cylindrical portion 22 formed directly below the head 21, and a screw extending further below the cylindrical portion 22. And a unit 23. A male screw is formed in the screw portion 23. The screw portion 23 includes a smooth screw portion 23a having a smooth thread surface on the distal end side,
A roughened screw portion 23b having a roughened thread surface on the head 21 side is provided. The surface of the rough screw portion 23b has a surface roughness Ry = 0.8 to 100 μm, preferably 1 μm.
A rough surface of 0 to 30 μm is formed.

FIG. 2B shows the thread rolled product 20 screwed into a through hole 25a of a plate material 25 made of metal, synthetic resin or the like while passing through a washer 24, while tapping the inner surface of the through hole 25a. It shows a state of being tightened. The formation region of the rough surface thread portion 23b of the thread rolling product 20 almost exactly matches the inner surface (tapped female screw portion) of the through hole 25a of the plate material 25. That is, the upper end of the rough surface screw portion 23b is substantially at the upper surface position of the plate member 25, and the lower end of the rough surface screw portion 23b is substantially at the lower surface position of the plate member 25. By forming in this manner, the screw portion 23 of the thread rolling product 20 is
5 and the through-hole 25 is tapped, a female screw is formed in the through-hole 25 by the smooth screw surface 23a at the tip, and the roughened screw portion 23b is screwed into the formed female screw. A loosening torque can be obtained, and loosening of the thread rolling product 20 due to vibration or the like can be prevented.

Here, if a rough surface is formed on the entire surface of the screw portion 23, the rough surface of the screw surface on the tip side will cut the inner surface of the through hole 25, so that FIG. The loosening torque is reduced in the tightening completed state shown in the figure, and the loosening prevention effect due to the roughening of the screw surface cannot be sufficiently obtained. Therefore, the rough surface is partially formed on the head 21 side of the screw portion 23 as described above. It is preferable to form the screw portion 23b.

The plate member 26 shown by a dashed line in FIG.
It is formed to be thicker than the length of the thread portion 23 of the thread rolling product 20. Even when the thread rolled product 20 is screwed into a hole (or a through hole) 26a formed in the plate 16, the roughened screw portion 23 b has the hole 26 a when the fastening is completed.
Is screwed to the portion on the opening edge side, and an improved loosening prevention effect can be obtained.

The thread portion 23 of the thread rolling product 20 was formed by rolling using the rolling die of the first embodiment, and the effect of the rough surface thread portion 23b was confirmed as follows. First, a screw portion 23 having a screw diameter of 4 mm and a length of 8 mm is formed, and a range of 3 mm below the neck of the head 21 (that is, a length range equal to the sum of the thickness of the washer 24 and the thickness of the plate material 25).
The above-mentioned rough surface screw portion 23b having a surface roughness Ry = 20 μm only
Is formed (Example 1) and the plate material 25 made of a steel plate having a thickness of 0.8 mm is tapped by the one having no roughened screw portion 23b (Comparative Example 1), and the same tightening torque is applied. Thus, the fastening state shown in FIG. Then, after tightening, the same vibration applied amount (50 at 60 Hz)
), And the loosening torque was measured and compared for each. As a result, in Example 1, the loosening torque was increased by about 30% as compared with Comparative Example 1.

Further, a screw portion 23 having a screw diameter of 3 mm and a length of 8 mm was formed, and the rough surface screw portion 23b having a surface roughness Ry = 20 μm was formed only within a range of 3 mm below the neck of the head 21 (implementation). Example 2) and the plate 26 made of an ABS resin having a thickness of 8 mm each were tapped with the one having no roughened screw portion 23b at all (Comparative Example 2), and the same tightening torque was applied to FIG. 2B. The fastening state shown in FIG. Then, vibration was applied so that the same amount of vibration was applied (50 hours at 60 Hz) after tightening, and the loosening torque was measured and compared for each. As a result, Example 2 was compared with Comparative Example 2
Approximately 20% less than the torque increased.

Further, the thread rolled product 20 has a threaded portion 23 having a thread diameter of 3 mm and a threaded portion length of 8 mm, and having a rough surface threaded portion having a length of 3 mm similar to the above (Example 3). Each of the screw portions 2 having no (comparative example 3)
3 was coated with an adhesive, screwed into a nut, and tightened with the same tightening torque to cure the adhesive. Thereafter, the same vibration as described above was applied, and the loosening torque was measured. As a result, the loosening torque of Example 3 was improved by about 10% as compared with Comparative Example 3. Further, in Example 3, the reproducibility of the loosening torque was good, and the variation range of the loosening torque was 50% in Comparative Example 3.
It was less than%.

[Second Embodiment] Next, a second embodiment, which is an example of the configuration of another rolling die for performing the same rolling process as described above, will be described with reference to FIG. The rolling die 30 of this embodiment is a so-called round die, and the illustrated example shows a die structure for performing through-rolling or step rolling (through-feed type rolling).

As shown in FIG. 3A, the rolling die 30 has a round die 31 having a die surface 31a having a cylindrical outer peripheral surface. A groove for forming a screw thread is formed on the die surface 31a, and the biting portion 311 and the parallel portion 3 are viewed in the axial direction (the processing direction S) of the round die 31.
12, the escape portion 313 is formed sequentially. Parallel part 3
12, a front processing region 312a in which only the thread groove is formed and a post-processing region 312b in which the surface of the groove is roughened. The surface of the groove is also roughened in the escape portion 313. In the present embodiment, all of the post-processing region 312b and the relief portion 313 are rough surface forming region portions.

In this embodiment, the round die 31 and
By rotating a round die 32 formed in the same manner as the round die 31 in the same rotation direction, and passing a round bar-shaped original material 35 therebetween in the axial direction (processing direction S), the die is formed. A male screw is formed on the outer peripheral surface of the original material 35 rotating in the opposite direction.

Also in this embodiment, the parallel portion 312 of the round die 31 has a position at a predetermined distance from the front end of the parallel portion 312 (that is, a distance corresponding to the length of the front processing region 312a in the processing direction S). As the start position, the rough surface forming region portion is formed from the start position to the rear in the processing direction S, so that the wear of the rough surface forming region portion is reduced as in the first embodiment, and the long life of the die is achieved. Can be achieved.

Further, it is similar to the first embodiment that the length of the pre-processed region 312a is preferably equal to or more than one rolling pitch, and the same is more preferable that the length is equal to or more than two rolling pitches. .

Also in this embodiment, the rough surface forming region may be formed only on one round die. In addition, by forming the rough surface forming area portion in an area limited in the width direction W of the dice (the circumferential direction of the die surface 31a corresponding to the width direction W of the flat dies 11 and 12), the thread rolled product is formed. The area limited in the axial direction can be selectively roughened.
Therefore, also in this embodiment, similarly to the first embodiment, a plurality of rough surface forming regions can be formed to be separated from each other. Further, similarly to the first embodiment, the life of the die can be extended by the correction processing for expanding the formation range of the rough surface forming region in the circumferential direction (width direction W).

[Specified Example 2 of Rolled Product] Next, a gear rolled product as an example of a rolled product other than the thread rolled product will be described with reference to FIG. This gear roll is a worm 40. As shown in FIG. 4A, a worm tooth forming portion 41 having a spirally extending tooth shape is provided on the outer periphery of the worm 40, and the center of the worm tooth forming portion 41 has a tooth-shaped surface. Roughened area 41 formed by roughening
a is provided. The rough surface forming region 41 a is formed as a limited part (region) in the worm tooth forming portion 41. In the center of the worm 40, a shaft hole 40 is provided.
a is formed.

Also in the worm 40, a tooth profile and a rough surface can be formed using the rolling dies of the first embodiment or the second embodiment. The worm 40 can be used, for example, with the motor shaft 61 of the motor 51 in a small motor with a reduction gear (geared motor assembly) shown in FIG.
This small motor with a speed reducer can be used, for example, for driving the opening and closing of a window glass of an automobile. Here, the motor shaft 61 is subjected to knurling, and the worm 40
The press-fitting fixation is more robust. The motor 51 is fixed to the gear case 52 via a screw, and the motor shaft 61 is rotatably supported by a bearing 53 in the gear case 52. The worm tooth forming portion 41 of the worm 40 meshes with a helical gear 62 rotatably mounted in a gear case 52.

In this small motor with a reduction gear, the drive torque output from the motor 51 is transmitted from the motor shaft 61 to the worm 40, and the worm 4
0 to the helical gear 62 and is taken out from the output shaft 62a. Here, by roughening the surface of the worm tooth forming portion 41 in the worm 40,
Since the friction coefficient between the worm tooth forming part 41 and the output gear 53 can be made appropriate, the anti-reverse property (reverse torque required when the input side is moved by the reverse operation from the output side is maintained, Can be improved).

FIG. 5 shows the structure of a small motor with a reduction gear. In this small motor with a reduction gear, a worm 40, a motor 51,
2, a bearing 53, and a motor shaft 61. The worm tooth forming portion 41 of the worm 40 meshes with the first helical gear 63, and the first helical gear 63 further meshes with the second helical gear 64. This is different from the one-stage reduction mechanism shown in FIG. 4 in that a two-stage reduction mechanism is configured such that rotation is taken out from the output shaft 64a of the second helical gear 64.

The method for producing the rolled die and the rolled product of the present invention is not limited only to the above-described illustrated examples.
It goes without saying that various changes can be made without departing from the spirit of the present invention. For example, as the rolling dies, other types of rolling dies such as planetary dies, in-feed type rolling dies using round dies, and the like,
Various types of rolling dies other than the above embodiments can also be used.

[0053]

As described above, according to the present invention,
Since the meshing structure can be formed and the surface thereof can be roughened, the manufacturing cost can be reduced and the productivity can be increased.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view and plan views (a) and (b) showing a structure of a rolling die according to a first embodiment of the present invention.

2A is a front view showing a thread rolled product as a specific example of a rolled product, and FIG. 2B is a partial cross-sectional view showing an example of use of the thread rolled product.
It is.

FIGS. 3A and 3B are a partial cross-sectional view showing a second embodiment of a rolling die according to the present invention, and an explanatory view showing a state during rolling;

FIG. 4 shows a gear rolled product (worm) as a specific example of a rolled product.
FIG. 2A is a schematic cross-sectional view showing a schematic shape of a gear and FIG. 2B is a cross-sectional view showing an example of use of a gear rolling product (a small motor with a reduction gear).

FIG. 5 is a cross-sectional view showing the structure of a small motor with a reduction gear.

[Explanation of symbols]

 10, 30 Rolled dies 11, 12 Flat dies 31, 32 Round dies 40 Worm (gear rolled product) 41 Worm tooth forming part 51 Motor 52 Gear case 53 Bearing 61 Motor shaft 62 Helical gear 63 First helical gear 62a, 64a Output shaft 64 Second helical gear 11a, 12a, 31a Die surface 111, 121, 311 Biting portion 112, 122, 312 Parallel portion 112a, 122a Pre-processing region 112b, 122b Post-processing region 112br, 122br, 123r Rough surface processing region Part 123,313 Escape part

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F16H 55/17 F16H 55/17 Z 55/22 55/22 (72) Inventor Kazuyuki Yamamoto Matsuhidai, Matsudo-shi, Chiba 430 Address F-term in Mabuchi Motor Co., Ltd. (reference) 3J009 DA18 EA04 EA05 EA06 EA12 EA19 EA21 EA23 EA32 EB02 EB08 ED17 FA14 3J030 AC03 AC10 BA03 BA05 BB06 BB09 BC02 BC03 BC10

Claims (15)

[Claims] 1. A method for forming a rolled product having an interlocking structure, comprising, at the front side, a biting portion into which an original material is introduced, and a main working portion for determining the shape of the biting structure is provided after the biting portion. In the rolling die having a die surface provided on the side, the die surface has a roughened surface of the meshing structure rearward from a starting position separated by a predetermined distance rearward from a front end of the main processing portion. A rolling die characterized in that a rough surface forming portion for forming is formed. 2. The rolling die according to claim 1, wherein the starting position is away from the front end of the main processing portion by one or more rolling pitches. 3. The rolling die according to claim 1, wherein the starting position is away from a front end of the main processing portion by a distance corresponding to a plurality of rolling pitches or more. 4. The rolling die according to claim 1, wherein the rough surface forming portion is formed by causing abrasive grains to collide with the die surface. 5. The rough surface forming portion is formed in a region limited in a width direction in a region behind the start position of the die surface so as to roughen only a part of the engagement structure. The rolling die according to any one of claims 1 to 4, wherein: 6. The rolling die according to claim 5, wherein a plurality of the rough surface forming portions are formed only in positions separated from each other in a width direction of the die surface. 7. A method for manufacturing a rolled product having a step of forming an interlocking structure with an original material, wherein an initial rolling step of performing rolling on the original material to form the interlocking structure; Forming a roughened surface while roughening the surface of the meshing structure while maintaining the meshing structure after the initial rolling step. 8. The method for manufacturing a rolled product according to claim 7, wherein in the initial rolling step, a plurality of roll forming cycles are repeatedly performed on the original material. 9. The method for producing a rolled product according to claim 7, wherein the initial rolling step and the rough surface forming step are continuously performed on an integrated die surface. . 10. After the rolling process of the rolled product is performed on the die surface, a rough surface forming surface portion for performing the rough surface forming step on the die surface is subjected to the initial rolling step. 10. A method for manufacturing a rolled product according to claim 9, further comprising: performing a correction process for extending the rolled product toward an initial rolling surface portion to be performed, and then further performing a roll forming process on another rolled product. . 11. The method for manufacturing a rolled product according to claim 9, wherein in the rough surface forming step, only a part of the surface of the meshing structure is subjected to a surface roughening treatment. 12. After forming the rolled product on the die surface, a formation area of a limited rough surface forming surface portion for performing the rough surface forming step is enlarged on the die surface. The method for manufacturing a rolled product according to claim 11, further comprising: performing a modification process for causing the rolled product to be further rolled. 13. A small motor with a worm speed reducer for transmitting the output of the small motor by a helical gear or a worm wheel and a worm, wherein a rough surface is formed on the worm surface by a rolling die. Small motor. 14. The compact motor according to claim 13, wherein the helical gear or the worm wheel is reduced in two steps. 15. A method for manufacturing a small motor with a worm speed reducer for transmitting the output of a small motor by a helical gear or a worm wheel and a worm, wherein the rough surface of the worm surface is formed by rolling with a rolling die. Motor manufacturing method.